Some display devices create an image by scanning a beam of varying intensity across a display surface. For example, in projectors, a light beam is scanned across a surface in a row and column pattern. In these display devices, the beam “paints” pixels on the screen row by row by modulating the intensity of the scanned beam as it passes over (or near) each display pixel location.
Some display devices may have multiple light sources of different colors. When the multiple light sources are perfectly “aligned,” each pixel is created by different colors of perfectly co-located light beams. In practice, it is difficult (and/or expensive) to perfectly align multiple light sources. As a result, the different color components of an image may be vertically and horizontally offset.